Leishmania-specific lymphoproliferative responses and IgG1/IgG2 immunodetection patterns by Western blot in asymptomatic, symptomatic and treated dogs.

Peripheral cell responses against Leishmania infantum and serology by IFAT and WB were determined in 87 untreated dogs from an endemic area (Madrid, Spain) and in 15 treated dogs (antimonials, allopurinol). All untreated symptomatic dogs (nine) did not show any lymphoproliferative response, whereas 21 out of 78 untreated asymptomatic dogs had a positive cellular response. Serum IgG(2) from dogs with clinical signs of patent leishmaniosis reacted with a variety of peptides (26, 29, 34-35.4, 42, 45, 50-57 and 67 kDa), but IgG(1) response was mainly directed against a 67-kDa peptide. Successfully treated dogs displayed a low immunoreactivity of both IgG(1) and IgG(2), particularly against 67 kDa, thus indicating the potential prognostic value of this region. Positive cellular response of dogs treated with good clinical progress was only observed up to 5-12 months post treatment. Untreated asymptomatic dogs with positive cell response showed a clear recognition by IgG(2) of approximately 67 and 45 kDa antigens, whereas IgG(1) did not recognise any antigen.